1. Field of the Invention
This invention relates to a fastener for attaching a trade or price tag to an article, or binding or joining a plurality of articles, and a method of making such a fastener. More particularly, it relates to a self-lockable fastener having a very long stringy member of any material and a method of making the same continuously.
2. Description of the Prior Art
There is known a fastener which is generally shown at 4 in FIGS. 1 and 2 and comprises a socket 1 having an opening 5, a head 2 which is engageable in the socket 1, and a filament 3 connecting the socket 1 and the head 2. This fastener is a unitary product molded from a thermoplastic synthetic resin. The head 2 is locked in the opening 5 of the socket 1 as shown in FIGS. 3A and 3B, whereby a tag or label T showing the price or quality of an article is attached thereto. The fastener is also used for binding or holding together two or more objects, such as members for sealing the cover of an instrument, slippers or sandals, or for closing the mouth of a bag.
The fastener has hitherto been made by a method which comprises injecting a thermoplastic synthetic resin into a mold to form a blank having an unstretched filament, and stretching the filament. This method, however, enables the filament to be stretched by only two or three times to a length not more than, say, 20 to 30 cm. This filament length does not permit the use of the fastener for any bulky article, such as a down jacket or overcoat.
Attempts have been made to manufacture a fastener having a very long filament, but have not turned out to be successful. The use of a long and slender mold has been proposed for making a fastener having a long filament. The molten resin does, however, not flow smoothly in the mold, because of the resistance which it receives from the mold, and also because the resin solidifies on the inner wall of the mold and reduces the inside diameter of the mold. It has only been possible to make a blank having a limited filament length.